Di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary has been used in household products, such as air care products, laundry detergent products, and fabric softener products, for several years. In such products, di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary delivers an anti-microbial benefit.
In terms of production process, currently fabric softener products including di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary are prepared in a batch process. Indeed, in such a batch step, different ingredients are added into a mix tank and then mixed. After the mixing period, follow-up steps in the production process, e.g., transporting the mixture of the ingredients to the packing lines, have to be performed. Moreover, when producing a different product having a different formulation, even for only slight formulation changes, the mix tank has to be rinsed, which requires the production process to be interrupted. In conclusion, batch production processes for making fabric softener products are generally considered inefficient and time-consuming.
Recently, continuous production processes for fabric softener products have been introduced. In a typical continuous process, such as an in-line process, base ingredients that constitute the main part of the fabric softener product, e.g., fabric softener active composition, flow through a line, and finishing ingredients, e.g., dye, perfume, silicone, etc., are added into the flow, to form the finished product. Moreover, in the in-line process, different fabric softener products with different finishing ingredients can be made by adjusting the addition of related finishing ingredients without a pause or stop. In conclusion, continuous processes for making fabric softener products are generally considered more efficient and less time-consuming as compared to batch processes. In view thereof, it is preferred to make fabric softener products using a continuous process rather than by a batch process.
However, it has been found that when di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary is formulated together with perfume into fabric softener active compositions in a continuous process, the finished fabric softener compositions become unstable due to an increase of viscosity, especially while being stored for a prolonged period of time.
Thus, there is a need for a continuous process for making a stable fabric softener composition comprising di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary and perfume. Indeed, it is the objective of the present invention to establish a continuous process for making a stable fabric softener composition comprising di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary and perfume.
It has been found that this objective can be met by the process according to the present invention. Specifically, the present invention provides a continuous process of making a fabric softener composition comprising di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary and perfume, wherein the viscosity of the fabric softener composition remains stable upon storage.
It is an advantage of the present invention to provide a continuous process of making a stable fabric softener composition comprising perfume and relatively high levels of di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary, e.g., more than 0.30% by weight of the fabric softener composition.
It is a further advantage of the present invention to provide a continuous process of making a stable fabric softener composition comprising perfume and relatively low levels of di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary, e.g., less than 0.23% by weight of the fabric softener composition, whereas in a certain portion of the process, the di(C6-C14)alkyl di(C1-C4 alkyl and/or hydroxyalkyl) quaternary may reach a high concentration.